Notes

In WordPress 3.21, the following recurring events are scheduled by the core: wp_version_check, wp_update_plugins, wp_update_themes, wp_schedule_delete, and (for the main site of multisite installs only) wp_update_network_counts.

In WordPress 3.21, the following single events are scheduled on demand by the core: publish_future_post, do_pings, importer_scheduled_cleanup.